Forging method for producing a hollow body

ABSTRACT

A COMPOUND ANNULAR BODY IS PRODUCED BY A FORGING OPERATION. INNER AND OUTER ANNULAR BODIES ARE TELESCOPICALLY ENGAGED ONE WITHIN THE OTHER, AND ARE PLACED WITHIN AN ANNULAR DIE HAVING RADIALLY OUTWARDLY EXTENDING PERIPHERALLY SPACED RECESSES. THE MATERIAL OF THE INNER ANNULAR MEMBER HAS A HIGHER MALLEABILITY THAN THAT OF THE OUTER ANNULAR MEMBER. AXIAL PRESSURE IS APPLIED TO THE CLOSELY FITTED ANNULAR MEMBERS IN THE DIE TO FORCE THE MATERIAL OF THE OUTER MEMBER INTO THE RECESSES TO FORM PROJECTIONS, AND TO FORCE THE MATERIAL OF THE INNER MEMBER INTO RECESSES IN THE INNER PERIPHERY OF THE OUTER MEMBER, THESE LATTER RECESSES RESULTING FROM THE RADIALLY OUTWARDLY DEFORMATION OF THE OUTER MEMBER. THE INNER AND OUTER MEMBERS ARE THUS INTERLOCKED AGAINST BOTH AXIAL AND ANGULAR RELATIVE DISPLACEMENT. THE TWO MATERIALS MAY BE METALLIC MATERIALS OR THE OUTER MEMBER MAY BE A METALLIC MATERIAL AND THE INNER MEMBER A SYNTHETIC RESIN MATERIAL. THE FORGING OPERATION MAY BE EITHER A HOT FORGING OPERATION OR A COLD FORGING OPERATION.

Jan. 12,:1971 TORU YAMADA ET AL $553,809

FORGING METHOD FOR PRODUCING A HOLLOW BODY Filed Jan. 5, 1968 4Sheets-Sheet 1 J6 /i 9 20 16 6 i 5 \J \i 5 i i Ax, 1

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TORu )UIMH A BY SENJY K/r/u/MA Jan. 12, 1971 TORU YAMADA ETAL 3,553,809

FORGING METHOD FOR PRODUCING A HOLLOW BODY 7 Filed Jan. 5, 196a 4Sheets-Sheet 2 INVENTOR. T Ru Yunnan sauna KITRJIMR Jan. 12, 1971 TORUYAMADA ETAL 3,553,809

FORGING METHOD FOR PRODUCING A HOLLOW BODY FiledvJan. 5, 1968 4Sheets-Sheet s JINVENTOR. TORU Y H H800 SENJYO KITHJIHR BY WWW Jan. 121971 TORU YAMADA ETAL v 4 3,553,809

FORGING METHOD FOR PRODUCING A HOLLOW BODY Filed Jan 5, 1968 4 Shets-sheaf, 4

INVENTORi TQR U Y H H 30 SENJYO KITnJ/Mn United States Patent 015cc3,553,809 FORGING METHOD FOR PRODUCING A HOLLOW BODY Torn Yamada,Nagoya, and Senjyo Kitajima, Gifu, Japan, assignors t Kabnshiki KaishaTokai Rika Denki Seisakusho, Nishikasngai-gun, Aichi Prefecture, JapanFiled Jan. 5, 1968, Ser. No. 695,909 Claims priority, application Japan,Jan. 25, 1967, 42/ 4,907, 42/ 6,538 Int. Cl. B21d 53/28; B21k 1/30; B23p/14 US. Cl. 29159.2 10 Claims ABSTRACT OF THE DISCLOSURE A compoundannular body is produced by a forging operation. Inner and outer annularbodies are telescopically engaged one within the other, and are placedwithin an annular die having radially outwardly extending peripherallyspaced recesses. The material of the inner annular member has a highermalleability than that of the outer annular member. Axial pressure isapplied to the closely fitted annular members in the die to force thematerial of the outer member into the recesses to form projections, andto force the material of the inner member into recesses in the innerperiphery of the outer member, these latter recesses resulting from theradially outwardly deformation of the outer member. The inner and outermembers are thus interlocked against both axial and angular relativedisplacement. The two materials may be metallic materials or the outermember may be a metallic material and the inner member a synthetic resinmaterial. The forging operation may be either a hot forging operation ora cold forging operation.

BACKGROUND OF THE INVENTION The present invention relates to a forgingmethod producing a hollow or annular body, such as a synchronizer ring,by a forging process. The present invention, further in details, relatesto a method producing a hollow or annular body, such as a synchronizerring, consisting of two components of respectively different materials,which are combined in an exact and close fit and of which the outer andinner components are made from two difierent materials havingrespectively different malleability.

A hollow or annular body, of which the outer and inner components aremade from different materials, has been commonly produced by suchprocesses as bonding, welding, compressing and shrink fittingprocedures, and there have been only a few suggestions to form such anannular body by combining a forging process and taking advantage of theplastic deformation characteristics of the materials.

A certain type of annular body, for example, a synchronizer ring for anautomobile transmission, has been produced from a pipe made from metalalloys of an expensive bronze group, by a welding process or a cuttingprocess, due to the necessity for meeting the required high abrasionresistance and mechanical strength and the required appropriatecoeflicient of friction of such ring. In spite of these requirements,one of the expensive materials to be employed for these inner and outercomponents can be very often substituted by an inexpensive materialwithout any problem. It has been extremely difficult, however, toprepare inner and outer annular components individually and preciselyformed by a preliminary process such as forging, cutting and otherprocesses, which should be selected depending upon the materials to beemployed, so that they can be exactly fitted in the succeeding bondingand other manufacturing processes as afore-mentioned. This has alsocaused an increase in manufacturing proc- 3,553,809 Patented Jan. 12,1971 esses. Moreover, another problem has been encountered in that thethus obtained annular body has not ample strength in the axial andperipheral directions of the composite or compound body, and especiallyin that, when, contacting surfaces at which two hollow or annularcomponents are joined together are tapered, it is very difiicult toincrease the strength in the combined surfaces of the components as highas that of a hollow or annular body made from a single material.

SUMMARY OF THE INVENTION In accordance with the present invention, anannular forging die is provided with a plurality of peripherally spacedradially outwardly extending depressions which may be in the form ofeither a tooth-disc or gear wheel or may be in the form of hemisphericaldepressions, for example. An annular piece, consisting of two componentshaving an exact telescoping interfit with each other, is placed into thedie. The outer component is made of metallic materials having arelatively large resistance to deformation as compared to the materialsused for forming the inner component, which latter may be, for example,a malleable and deformable plastic or synthetic resin material. Byapplying axial pressure to the composite annular body, the material ofthe outer component is partly distorted or extruded into the depressionsof the annular die, the axial pressure being provided, for example, by apunch member of a press, Successively, the material of the innercomponent is distorted or radially extruded to flow into recessesresultantly created around the inner periphery of the outer material bysuch distortion of the latter, so that materials of the outer and innercomponents are united in partial abutment in the peripheral direction,whereby a hollow or annular body having improved com posite strength canbe obtained.

An object of the invention is to provide an improved method forproducing a composite annular body.

Another object of the invention is to provide such a method in which thestarting member comprises two or more telescoped and closelyinterfitting annular bodies having a relatively short axial length.

A further object of the invention is to provide such a method in whichthere are a pair of such annular bodies with the material of the outerannular body being less malleable than the material of the inner annularbody.

Another object of the invention. is to provide such a method in whichthe starting piece or body is axially compressed in a forging die memberin the form of an annular ring having radially outwardly extendingrecesses formed in its inner periphery in peripherally spaced relation.

A further object of the invention is to provide such a method in whichthe starting body, engaged in the annular die ring, has pressure exertedthereon by a punching member movable in axial alignment with the diering and projectable into the annular body.

Another object of the invention is to provide such a method in which, inresponse to the axial pressure on the starting body, the material of theouter body is forced radially outwardly into the depressions in the diering and the material of the inner body is forced radially outwardlyinto the resulting depressions in the inner surface of the outer bodymember.

For an understanding of the principles of the invention, reference ismade to the following description of typical embodiments thereof asillustrated in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings showingpreferred embodiments of the present invention;

FIG. 1 is a longitudinal sectional view of one form of forging apparatusused in the method of the present invention, wherein dotted lines show apunching member when fitted into a die member,

FIG. 2 is a plan view of the die member,

FIG. 3 is a side elevation view, partly in radial section, illustratinga starting body comprising two annular members having a closeinterfitting telescopic fit with each other and having a short axiallength,

FIG. 4 is a partial plan view of another example of a hollow or annularbody obtained by the method of the present invention,

FIG. 5 is an explanatory sectional view especially showing flow ofmaterials used in producing the body of FIG. 4,

FIG. 6 is an explanatory sectional view showing flow of a material usedin producing a hollow or annular body of which the outer and innercomponent are made from a single material,

FIG. 7 is an elevation view, partly in radial section, of anotherembodiment of annular die ring usable with the invention method, and

FIG. 8 is an end elevation view, partly in section, of a compositeannular body produced using the die shown in FIG. 7.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIGS. 1 and 2, fixed bysupporting members 1 through 4 is a forging die member 5, which has adiametrically reduced part 6, a diametrically medium part 7 and atooth-like form depression forming part 8, these parts being arranged ina step-like state upwardly from the bottom. On tooth form depressionforming part 8, as shown in detail in FIG. 2 are arranged a plurality ofdepressions 9 arranged in spaced relation in a peripheral row, in whicha plurality of peripherally spaced tooth form radial projections are tobe formed. The bottom surface of the diametrically reduced part 6 of theforging die member 5 is defined by the upper surface of an ejector 11,which has a peripheral shoulder 11a supported in abutment with a support member 4, and which is pushed upwardly into die member 5, forejecting a finished annular body, in coaction with a cylindrical stem.17 is a punching member which is fixedly supported by supporting members14 through 16 mounted fixedly on a ram 13. Punching member 17 has adiametrically reduced part 18, whose peripheral edge is slightly taperedin the upward direction in substantial correspondence with the reducedpart 6 of the die member 5 and whose bottom surface confronts, at aslightly spaced distance, the upper surface of the ejector 11 whenmember 7 is pushed into die 5, a tapered part 19 corresponding to thediametrically medium part 7 and the tooth form depression forming part 8of die member 5, and a bottom end surface 20 confronting, at a slightdistance and/or in a close contact, the upper surface of die member 5including the open upper ends of depressions 9.

FIG. 3 shows one example of a compounded hollow or annular piece 21 tobe processed, of which innner component 23 is made from soft steel andouter component 22 is made from an alloy of a bronze group, for example,cobalt-bronze. In hollow piece 21, the material of outer component 22,having a higher softening point has far higher deformation resistance incomparison with the material of inner component 23.

The inner diameter of the compounded piece 21 must be larger than thediameter of the under part of the punching member 17, and it must benoted that the difference between these diameters will have a greatinfluence on the flow of materials during heat working.

The compound annular piece 21, during the forging operation, isshortened in an axial direction, and the thicknesses of the outercomponent 22 and the inner component 23 are correlatively decideddepending upon the configurations of the die member 5 and the punchingmember 17 which is pushed into the interior thereof.

Accordingly, a dimension of the annular piece 21, that is, in detail, anouter diameter, an inner diameter, a longitudinal or axial length and aratio of the thicknesses of the outer component 22 and the innercomponent 23 must be decided taking into consideration the difference indeformation resistance between materials of the outer component 22 andthe inner component 23 and the configurations of the die member 5 andthe punching member 17.

FIGS. 4 and 5 illustrate a synchronizer ring for an automotivetransmission formed by the forging operation performed upon the startingbody shown in FIG. 3, the forging operation being a hot forgingoperation using the apparatus shown in FIGS. 1 and 2. When punchingmember 17 is projected into the interior of starting body 21 positionedin annular die 5, the metallic material of inner component 23 is, by theforging and contacting pressure of the punching member 17, caused toflow downwardly in that portion confined between the outer periphery ofpart 18 of the punching member 17 and the inner peripheral surface ofannular piece 21. The displaced material is forced into the gap formedbetween the bottom end of part 18 and the upper surface of the ejector11 to form a flash directed radially inwardly of the annular piece. Theupper end of annular piece 21 is impacted, under pressure, by surface 20of the punching member 17, when the member 17 is pushed into piece 21.Meanwhile, the material of the outer component 22 having relatively highdeformation resistance, without following the aforementioned flow of thematerial of the inner component 23, forced radially outwardly, as at 33,into depressions 9 to form plastic deformed protrusions 35, due to thepressure of punching member 17. The material of inner component 23 is,in turn, caused to flow into the recesses 33, formed on the innerperiphery of the outer member opposite each depression 9, as a result ofthe distortion of the material of the outer member. Thereby, a unitingof the inner and outer components and a compound of these materials inthe annular piece 21 are created by close abutment and fusion ofparticles of these materials. Such conjugation and compounding extendthroughout the entire engaging surfaces of the outer component 22 andthe inner component 23, and the contact of these materials inside theaforementioned radially distorted protrusions especially serves toincrease the compounded strength of the finished body 31 in the axialand peripheral directions thereof.

FIG. 6 shows an explanatory sectional view of an annular body forged, ina forging apparatus as shown in FIGS. 1 and 2, from an annular piece ofa single metallic material for the outer and inner component made in aconfiguration identical to that of the annular body as shown in FIG. 6,wherein the plastic fluidity of the metallic material is completelyequal, so that distorted flow of the metallic material is minimized indepressions 9 where the material protruded. It will be apparent that theefiiciency of the compounded materials having different flowcharacteristics is clearly proven by comparison of this figure and FIG.5.

FIG. 7 illustrates another embodiment of the invention wherein anannular die member 107 is divided into three arcuate sections 108 whoseinner surfaces are circular arcs. Die member 107 is not designed to formtooth type projections around the outer periphery of a finishedcomposite annular body, as in the embodiment of the invention shown inFIGS. 1 and 2, but is formed with a plurality of peripherally spacedhemispherical recesses or depressions in its inner annular surface, allbeing centered on a common diametric plane of member 107 intermediatethe axially opposite ends thereof. The punching member used with the die107 can be a simple type of punch. An annular piece 121 to be processedin this example is a composite hollow piece consisting of an outercomponent 122, made from aluminium alloy, and an inner component 123,made from poly-carbonate plastics which is subject to plasticdeformation by forging pressure.

FIG. 8 shows a sectional view of a compounded hollow body forged in coldworking in the forging apparatus as shown in FIG. 7. In this example,the material of the outer component 122 is compressed to be distortedand flowed into depressions 109, as indicated at 133 by pressure appliedto the upper end of the piece to be processed by the punching member,and the material of the inner component 123 is forced into recesses 134formed inside of depressions 109, whereby the materials of the outercomponent and the inner component are sealed in close meshinginterfitting with one another. Verruci-form projections133a, formedaround the outside of part 133, can be cut off in practical use of theproduct, depending upon application thereof.

What is claimed is:

1. A forging method for producing a compound annular body, comprisingthe steps of providing an annular forging die having peripherallyspaced, radially outwardly extending recesses in its inner periphery;forming a composite starting body by inserting an axially short innerannular member into an axially short outer annular member with a closetelescopic fit, the two members being substantially equal in length andthe material of the outer member having a higher resistance todeformation than that of the inner member; positioning the starting bodyin the forging die; and advancing a forging punch into pressure exertingengagement within the inner annular member while exerting forgingpressure axially against the outer end of the starting body to axiallycompress the starting body while deforming material of the outer memberinto the die recesses with subsequent plastic flow of the material ofthe inner member into resulting peripherally spaced recesses in theinner surface of the outer member each substantially aligned with a dierecess; whereby the inner and outer members are interlocked againstrelative angular and axial displacement.

2. A forging method for producing a compound annular body, as claimed inclaim 1, including the step of subsequently removing the resultingradially outwardly extending projections from the outer periphery of theouter member.

3. A forging method for producing a compound annular body, as claimed inclaim 1, in which both the inner annular member and the outer annularmember are metallic annular members.

4. A forging method for producing a compound annular body, as claimed inclaim 1, in which the material of the outer annular body is metallic andthe material of the inner annular body is a plastic composition.

5. A forging method for producing a compound annular body, as claimed inclaim 1, in which the radially outwardly extending recesses in the innerperiphery of said die produce gear-tooth-like projections from the outerperiphery of the outer annular member.

6. A forging method for producing a compound annular body, as claimed inclaim 5, in which the die recesses open through the outer axial endsurface of the die.

7. A forging method for producing a compound annular body, as claimed inclaim 1, in which the die recesses are substantially hemisphericalrecesses.

8. A forging method for producing a compound annular body, as claimed inclaim 7, including the step of providing an annular forging diecomprising plural arcuate separable sections conjointly defining theannular forging die; the die recesses being intermediate the axiallyopposite ends of the die.

9. A forging method for producing a compound annular body, as claimed inclaim 6,. including the step of providing a starting body seating memberwithin the annular die; and limiting the advance of the forging punch toa position in which its inner end is spaced slightly from the seatingmember; whereby, under the forging pressure, there is a plastic flow ofthe material of the inner member radially inwardly into the spacebetween the end of the forging punch and the surface of the seatingmember.

10. A forging method for producing a compound annular body, in which theforging operation is a hot forging operation.

References Cited UNITED STATES PATENTS 1,766,865 6/1930 Williams et al.29159.2X

2,232,973 2/1941 Rood 29523UX 2,044,924 6/1936 Timken 29-523 3,247,5844/1966 Oles 29523X FOREIGN PATENTS 505,677 5/1939 Great Britain 29-523CHARLIE T. MOON, Primary Examiner U.S. Cl. X.R. 29523; 74-457

